Boletus edulis/ Karl Johan rørhat.

 

Boletus edulis, English names: penny bun, porcino or cep, is widely distributed in the Northern Hemisphere across Europe, Asia and North America; it does not occur naturally in the Southern Hemisphere although it has been introduced to various countries there. It is a very popular mushroom in Scandinavia, where it grows in big numbers. It is known as the Karl Johan mushroom all over Scandinavia,  named after the Swedish king Karl XIV Johan, who liked this mushroom very much.

Karl Johan, stig bachmann nielsen, Naturplan Foto.

In Italy it is described as the wild mushroom par excellence. The Italian name is porcini, meaning "little pigs", but it is often called the king which underlines its status as the most outstanding of all mushrooms. In Toscana it is often cooked with thyme. In a simple dish like an omelet, this well-tasting mushroom shows to its best advantage. In Russia it is known as White Mushroom, meaning noble. In North America are found a number of species closely related to Boletus edulis. (see link below)

The English name porcino seems to derive from the Roman time in Britain, since the Italian name is porcini. I'll call it porcino in this small article. It is one of the most sought after mushrooms of Europe. Many boletus are edible, some with a good taste, others tasteless and others unpleasantly bitter. Boletus edulis is the best - edulis means eatable or edible. Porcino is considered one of the safest wild mushrooms to pick for the table as there are no poisonous species that closely resemble it. The mushroom has to be plucked while young, old porcinos get soft and swampy. Specimens should not be collected from potentially polluted or contaminated sites. Boletus edulis is known to be able to tolerate and even thrive on soil that is contaminated with toxic heavy metals.


  

 

The cap is greasy (especially after rain), brown to greybrown, it is often a little nubbly, it is about 10-15 cm diameter, but some porcinos might be 25 cm in diameter. On occassions it can reach 35 cm in diameter and 3 kilo in weight. Like other boletes it has tubes extending downward from the underside of the cap, rather than gills. The pore surface of the porcino's fruit body is whitish when young, but ages to greenish yellow. The stout stem is white or yellowish in colour,  about 5-10 cm tall and 2-4 cm thick, equipped with a fine white network, the brownish stem species have often only a clear white net at the top near the cap - the stem has usually a big bump lowest, which can reach high up on the stem, and this is a good indicator that it is a porcino, but other informations should be used for safety's sake. 

photo:GB

Boletus edulis lives in forest, but it is not choosy, it is found in both softwood and hardwood forests, often in boundaries between those two forest types. It is a common fungi in the Danish forests and can be harvested in large numbers. It is a rather big mushroom, only a few specimens are necessary for a meal. This mushroom is held in high regard in many cuisines. The flavour has been described as nutty and slightly meaty with a smooth creamy texture and a distinctive aroma, which reminds about the leaves in the forest, where it grows.The stem is good as raw snacks, and the cap can be cooked in many ways - sautéed with butter, ground into pasta, in soups and in many other dishes. The delicate nut-taste and the creamy meat its good for risotto and pasta-dishes and sauces and as a accompaniment to venison or a big steak. Porcini risotto is a traditional Italian autumn dish. All boletus give off much liquid during making, which has to be removed or used for a fond or soup.

Boletus edulis has not been successfully grown in cultivation, but is available fresh in autumn. It is sold fresh in markets in summer and autumn and dried or canned at other times of the year. It keeps its flavour after drying. Distributed worldwide to countries where they are not otherwise found.  It is low in fat and high in protein, vitamins, minerals and dietary fibre.

Løvenholm forest, stig bachmann nielsen Naturplan Foto

Confusion: Tylopilus félleus, fel meaning bile because of its bitterness, (DK: Galde Rørhat)  and Bolétus réticulatus, called Summer cep, (DK: Sommer Rørhat). Boletus edulis is often confused with this very bitter Tylopilus felleus, but can be distinguished by the reticulation on the stalk; in porcino it is a whitish net-like pattern on a brownish stalk, whereas it is a dark pattern on white in Tylopilus. The porcino has white pores, while the other has pink. If in doubt, tasting a tiny bit of flesh will yield a bitter taste.The Summer cep's flesh is less firm than other boletes. The most similar mushroom  may be the Devil's bolete (Boletus santana), which has a similar shape, but has a red stem and stains blue on bruising.

"I confess, that nothing frightens me more than the appearance of mushrooms on the table, especially in a small provincial town."
Alexandre Dumas, early 19th century.

5 good edible mushrooms:
Boletus edulis: Porcino, Cep, Penny Bun ; (DK: Karl Johan)   
Agarius campestri: Field champignon, in North America Meadow champignon, (DK: Mark champignon);
Cantharellus cibarius: Chanterelle, (DK: Almindelig kantarel);
Craterellus tubaeformis: Yellowfoot, Winter mushroom, Funnel chanterelle, ( DK: Tragtkantarel);
Craterellus cornucopioides: Trumpet of death, Black chanterel, Black trumpet, Horn of plenty,  (DK: Stor Trompetsvamp).




Source: Politikens Svampebog, Svampe i Skandinavien, Danmarks Fugle og Natur, Felthåndbogen,Wikipedia.  

I'll have to add this:
Whether or not Boletus edulis occurs in North America is up for debate, says this website from: Mushroom Experts Com.